The supply lines, for example, can be provided for the transmission of electric power and/or compressed air, and the trailer can be a semitrailer or any other kind of trailing vehicle.
Coupling systems are known in various configurations. In the most simple case, there is a plug and a socket, which are fastened to more or less elastic lines. After the mechanical connection of trailer and tractor vehicle, it is also necessary to join the supply lines together. For this, a person must connect the plug and socket by hand. Before uncoupling the trailer, the coupling system must again be separated. If one forgets to do so, the coupling system will be torn apart.
Thus, there are efforts under way on the one hand to automate the connecting and separating of coupling systems and on the other hand to make it more safe.
Therefore, in the case of road trains, it was already attempted in the past to lead the supply lines through the kingpin of the trailer, which in the coupled state of trailer and tractor vehicle cooperates with a corresponding mating piece in the fifth wheel. Such a coupling system is described, for example, in EP 0 816 211 A2. However, this device has the drawback that the cross section of the kingpin only allows a limited number of supply lines and, what is more, the kingpin is affected in terms of its strength. Furthermore, there is a high risk of contamination, especially due to lubricating grease and the solids adhering to it, and an increase in the structural height due to the plug being led out below or above the kingpin.
One prior art of this kind is disclosed by DE 101 55 056 A1, whose plug-in coupling system has a wedge-shaped support element with a plug, which is mounted on the kingpin of the trailer so that it can swivel, and located in the entry opening of the fifth wheel when the trailer is coupled up. Then, an actuator with a plug arranged on it extends out from a side wall of the entry opening and makes contact with the plug of the support element. However, this system is arranged in a region of the fifth wheel which already accommodates a number of other structural components, especially the mechanical locking. Therefore, it is only possible to accommodate a small number of contacts in the coupling system, so that, for example, the pressurized air lines still have to be hooked up by hand.